Lawn mower sharpening device



Feb. 2, 1932 M, MgCHALsKl 1,843,830

LAWN MowER SHARPENING DEVICE Filed April 20, l1931 5.56 .70 55 .M57 4Z Z3 Z6 ,lil/352 INVENTOR.'

BY @wma/ C0.

Patented Feb. 2, 1332 UNITED STATES leerse MARTIN MIGHALSKI, or Nonrrr CHICAGO. rLLrNois LAWN Mov/'En sri-1Anrannue. :envien y Y Application filed April 20,

This invention relates to certain novel iniprovements in lawn mower sharpening devices7 and has for its principal object the provision of an improved construction of this character which will be highly efficient in use ,and economical in manufacture. y

Thesalient object of this-invention is to provide an'improved device for sharpeningthe blades ofaa lawn mower.

Another object of the invention is to provide a sharpening device which may be detachably mounted on a lawn mowerso that astlie blades of the mower revolve they will Fig. 1 is a front elevational view of a typical lawn mower showing a preferred form of the invention mounted thereon;

Fig. 2 is a sectional detail view taken substantially on the line 2-2 in Fig. 1;

Fig. 3 is a perspective View of a preferred form of construction of the invention;

Fig. 4 isa perspective view of a clamping elementembodied in theinvention; and

Fig. 5 is a sectional detail view taken substantially on the line 5-5 in Fig. 3.

Referring to the drawings wherein a preferred embodiment of the invention is depicted. there is generically indicated at 10 a typical lawn mower construction with which the handle structure 1l is associated. While in the present instance the mower l0 is illustrated as being a hand driven mower it is to be understood that the present invention might be used on power driven mowers without departing from the purview thereof.

Embodied in the lawn mower 1() are the usual wheels 12 and 13 with which are assoi931.V sensi No. 53i,534.

ciated gears toV drive the rotatablejshaft' 14. Mounted on the shaft 14 .at intervals therealong are collars'sn'ch asl, 16 and 17 from which'project arms such as 18, 19j, 20 and 21, as may be seen by reference to Fig. l2. Mountedv on they arms of the collars-15, 16 andl17 Vare the cutting blades 22, 23, 24, and 25. EX- "tending between the gear housings 26 and 27,

is. arrod 28 on-which my improved device is intended to be mounted., it being understood f construction may ben of, any approved type My improved device is generically indicated at 29 and is intended to beniounted on the rod 281er like supporting member extending between the wheels of the mower. Indicated at 30 is a substantially rectangular plate which may be of any suitable material Aand inthe present, instance is shown` as being made of wood. Adhesively secured' to the sides of the plate 3:0 are abrasive surfaces '31 and'32 and these surfaces are provided by securing to the plate 30, by means of suitable `adhesive binding agent, a suitable abrasive dust or granulated substance such as emery, carborundum or the like. It has been found impracticabl'e to provide rigid slabs of abrasive inateri al since these are subj ect to crackin g when used on the mower due to the impactof the blades and the shock thereof.

There is secured to the plate 30 by means of a bolt and nut structure 33 a hook element '34 and a similar hook element 35 is attached to the plate 30 by means of a bolt and nut structure 36. Y Ars shown in Fig. 1. these hook elements are mounted on the rodr28 so as` to support the plate 30 and the abrasive surfaces adapted to receive the rod 28. The clip 37 inl cludes an arcuate portion 39, the lower end 40 of which bears against the plate 30 as best shown in Fig. 2. Integral with the portion 33 is a depending portion 41 and extending through this portion 41 and the arcuate 6o l that the hereinbeforeydescribed. manner ofA since the same forms nopart of this invention. Y

portion 39 is a threaded bolt 42 on which is provided, exteriorly of the arcuate portion 39, a nut 43.

It will be seen, therefore, that when the plate 30 is in position as shown in Figs. l and 2, and the spring clip member 87 disposed with the rod 28 extended through the section 38, the nut L8 and bolt 42 may be tightened to force the arcuate leaf portion 39 against the front face of the plate 8O so as to force the abrasive surface 31 against the blades of the mower as the same are rotated.

After the abrasive 3l has been worn away the clips or hooks 34 and 35 may be detached l5 and the plate 30 turned so that the abrasive face 32 may then be used in the manner clearly illustrated for the face 3l. It will be seen, therefore, that as the blades of the mower rotate the beveled cutting edges thereof will en- 2o gage the abrasive face and, since the spring clip 37 forces the plate 30 inwardly toward the blades, the cutting edges of the blades will be sharpened as they'engag'e the abrasive surface.

' From the foregoing description of the invent-ion it will be .apparent that I have provided an improved sharpening` device for lawn mowers which while being simple in construction and economical in manufacture v effectively accomplishes its intended purpose.

lVhile I have illustrated and described the preferred form of construction for carrying my invention intoeffect, this is capable of variation and modification, without departing` from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modificati-ons as come within the scope of the ap- 40 pended claim.

Having1 thus described my invention what I claim as new and desire to protect by Letters Patent is:

lawn mower sharpener Comprisinga plate, abrasive means adhesively secured to said plate. means for detachably mounting' said plate on the mower in the path of movement of the blades, so that said blades during rotation will engage said abrasive means, and yieldable mea-ns for urging' said plate toward the cnttiinqr blades whereby said blades will' frictionally engage said abrasive means, said yieldable means including a leaf spring including a convoluted portion adapted to be mounted on the mower and including' an arcuate portion engagingl the front side of said plate to force said plate and said abrasive means toward the blades of the mower.

In testimony whereof I affix my signature.

MARTIN MroHALsKr. 

